Download Potentials for Adaptation to Climate Change in Human

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1/31/07
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DRAFT: Please do not quote
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Effects of Global Change on Human Settlements
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Lead Author: Thomas J. Wilbanks, Oak Ridge National Laboratory
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Contributing Authors: Paul Kirshen, Tufts University; Dale Quattrochi,
NASA/Marshall Space Flight Center; Patricia Romero-Lankao, NCAR; Cynthia
Rosenzweig, NASA/Goddard; Matthias Ruth, University of Maryland; William
Solecki, Hunter College; Joel Tarr, Carnegie Mellon University
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Contributors:
Georgia Tech
Peter Larsen, University of Alaska-Anchorage; Brian Stone,
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Human settlements are where people live; so effects of climate change on
settlements are directly relevant to human well-being. This chapter briefly
summarizes current knowledge about climate change vulnerabilities and impacts
in human settlements in the United States, potentials for adaptation to climate
change in U.S. settlements, conclusions and recommendations based on what is
currently known, and research needs to improve the available knowledge.
Introduction
As such recent events as Hurricane Katrina in 2005 and electric power outages
during the hot summer of 2006 have demonstrated dramatically, climate can
affect U.S. cities and smaller settlements. Settlements, and in particular larger
urban areas, have often been the focus of human efforts to control exposures to
climate and other manifestations of nature, reducing their importance in our
everyday lives as we live and work inside climate-controlled structures,
surrounded by natural features that are engineered to fit our convenience.
But it has been sobering to find that even the world’s most advanced societies
cannot ignore climate, even in built areas. Climate affects the costs of assuring
comfort at home and work for the affluent and, for the poor, levels of comfort in
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terms of temperature and humidity. Climate provides inputs for a good life:
water, products and services from agriculture and forestry, pleasures and tourist
potentials from nature, biodiversity, and outdoor recreation. Climate affects the
presence and spread of diseases and other health problems, and it is associated
with threats from natural disasters: floods, fires, droughts, wind, hail, ice, heat,
and cold waves. If the climate is changing, therefore, then that is important news
for U.S. settlements.
Certain kinds of circumstances are likely to cause particular concerns for cities
and towns in the United States as they consider possible implications of climate
change. For instance, some settlements are located in especially vulnerable
areas, such as on or near coasts subject to storms and sea-level rise. Some
have economies linked to economic sectors especially sensitive to climate
variation, such as agriculture or tourism. Some settlements are already stressed
by other forces that might interact with climate change effects, such as rapid
population growth, aging physical infrastructures, poverty, and social friction.
Some are considerably dependent on linkage systems, such as bridges or
electric power lines, that could be vulnerable to impacts of climate change.
On the other hand, some U.S. settlements may find opportunities in climate
change. Warmer winters are not necessarily undesirable. Periods of change
tend to reward progressive, well-governed communities. Considering climate
change effects may help to focus attention on other important issues for the longterm sustainable development of settlements and communities. In many
regards, U.S. cities and counties – along with some U.S. states – have been
more active in considering climate change as a policy issue than has been the
case at the national level, not because they are required to do so by national
policy but because they choose to do so in order to respond to local driving
forces. In particular, larger settlements are sometimes more aware of their roles
as emitters of greenhouse gases, and therefore a part of the causes of climate
change, than of their possible vulnerabilities to impacts (see Potentials for
Adaptation to Climate Change, below). Furthermore, planning for the future is an
essential part of public policy decision-making in urban areas. Since
infrastructure investments in urban areas are often both large and difficult to
reverse, climate considerations are increasingly perceived as one of a number of
relevant issues to consider when planning for the future (Ruth, 2006). If U.S.
settlements, especially larger cities, respond effectively to climate change
concerns, their actions could have far-reaching implications for human wellbeing, because these areas are where most of the U.S. population lives, large
financial decisions are made, political influence is often centered, and many
technological and social innovations take place.
Meanwhile, our pattern of human settlement in the U.S. is changing. Besides
shifts of population from frost-belt to sun-belt settlements, patterns are changing
in other ways as well. For instance, what once appeared to be an inexorable
spread of households from urban centers to peripheries is showing renewal in
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many city centers as metropolitan areas continue to expand across multiple
jurisdictions (Solecki and Leichenko, 2006). And modern information
technologies are enabling people to perform what were historically urban
functions from relatively remote locations. Assessing effects of climate change
on human settlements in the U.S. is complicated by the fact that we are changing
in our settlement patterns and preferences.
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Determinants of vulnerabilities/impacts
These are important questions for both our settlements and the nation as a
whole, but the ability to illuminate the issues is severely limited by the fact that
little research has been done to date specifically on effects of climate change on
U.S. cities and towns. Reasons appear to include (a) a general lack of support
for climate change impact research, compared with climate system and
mitigation research, (b) limitations in capacities to project climate change impacts
at the geographic scale of a metropolitan area (or smaller), and (c) the fact that
none of the federal agencies currently active in climate science research has a
clear responsibility for settlement impact issues. To some degree, gaps can be
filled by referring to several comprehensive analyses that do exist, to literature on
effects of climate variation on settlements and their responses, to research on
climate change impacts on cities in other parts of the world, and to analogs from
the U.S. historical experience with responses of urban areas to significant
environmental changes (see Box: U.S. Urban Responses to Environmental
Change: A Historical Perspective). But this is little more than a place to start.
Whatever the reasons, the current knowledge base provides only a shaky basis
for developing conclusions and recommendations at this time. In many cases,
the best that can be done right now is to sketch out the landscape of issues that
should be considered by both urban decision-makers and the research
community as a basis for further discussion, offering illustrations from the
relatively small research literature that is now available.
Climate Change Vulnerabilities and Impacts in Human
Settlements
Consider first the possible impacts of climate change on settlements in the U.S.,
what determines the vulnerability of a particular settlement to such impacts, and
how the impacts could affect our settlement patterns and various systems related
to those patterns.
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In many cases, it has been difficult to project impacts of climate change on
human settlements in the U..S., in part because climate change forecasts are not
specific enough for the scale of settlement decision-making (as for other
relatively local-scale impact questions) but more profoundly because climate
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U.S. URBAN RESPONSES TO ENVIRONMENTAL CHANGE:
A HISTORICAL PERSPECTIVE
Over time, American cities have been affected in many ways by environmental change and
environmental events. Anthropogenic actions or beliefs, however, in many cases shaped the severity of
the environmental impacts. Founders of cities often evidenced a lack of care in regard to their sitting,
focusing on the positive aspects of a location such as commercial or recreational possibilities or the
availability of a precious mineral but ignored risks such as flooding potential, limited water, food or fuel
supplies, or the presence of health threats. Oftentimes urbanites severely exploited their environments,
polluting ground water and adjacent water bodies, building in unsafe and fragile locations, changing
landforms, and filling in wetlands. Construction of the urban built environment involved vast alterations
in the landscape, as forests and vegetation and wildlife species were eliminated and replaced by
highways, suburbs, and shopping malls. The building of wastewater and water supply systems had the
effect of altering regional hydrology, creating large vulnerabilities. Still other cases of the disregarding
of environmental risk to cities involved sets of beliefs such as the weather was changing permanently for
the good, technology could solve problems, or new resources could be discovered.
The response of many cities to environmental change and increases in environmental risk was to seek
ways to modify or control environmental events using technology. Cities exposed to flooding built
levees and seawalls and channelized rivers. When urbanites depleted and polluted local water supplies
cities went outside their boundaries to seek new supplies. building reservoirs, aqueducts, and creating
protected watersheds. When urban consumption exhausted local fuel sources, cities adapted to new
fuels, embraced new technologies, or searched far beyond city boundaries for new supplies. Many of
these actions resulted in the extension of the urban ecological footprint, so that urban growth and
development impacted not only the urban site but also increasingly the urban hinterland and beyond.
There are few examples of environmental disasters or climate change actually resulting in the
abandonment of an urban site. One case appears to be that of the Hohokam Indians of the Southwest,
who built extensive irrigation systems, farmed land, and built large and dense settlements over a period
of approximately 1,500 years. Yet, they abandoned their settlements and disappeared into history. The
most prominent explanation for their disappearance is an ecological one - that the Hohokam irrigation
systems suffered from salinization and water logging, eventually making them unusable. Other factors
besides the ecological ones may have also entered into the demise of their civilization and abandonment
of their cities, but the ecological explanation appears to have the most supporters.
In the case of America in the 19th and 20th centuries, however, no city has been abandoned because of
environmental or climatic factors. Galveston, Texas suffered from a catastrophic tidal wave but still
exists as a human settlement, now protected by a extensive sea wall. Johnstown, Pennsylvania has
undergone major and destructive flooding since the late 19th century, but continues to survive as a small
city. Los Angeles and San Francisco, are extremely vulnerable to earthquakes, but still continue to
increase in population. And, in coming years New Orleans almost certainly will experience a hurricane
as or more severe than Katrina, and yet rebuilding goes on, encouraged by the belief that technology will
protect it in the future. Whether or not ecological disaster or extreme risk will eventually convince
Americans to abandon their cities, as the Hohokam did, has yet to be determined.
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(References to be added)
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change is not the only change being confronted by settlements. More often,
attention is paid to vulnerabilities to climate change, if those changes should
occur.
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Projected impacts of climate change on settlements in the U.S
(1) Vulnerabilities to or opportunities from climate change are related to three
factors, both in absolute terms and in comparison to other areas (Clark et
al., 2000):Exposure to climate change. To what climate changes is a
place likely to be exposed: temperature or precipitation changes, changes
in storm exposures and/or intensities, changes in the sea level?
(2) Sensitivity to climate change. If primary climate changes were to occur,
how sensitive are the activities and populations of a settlement to those
changes. For instance, a city dependent substantially on a regional
agricultural or forestry economy, or to the availability of abundant water
resources, might be considered more sensitive than a city whose
economy is based mainly on an industrial sector less sensitive to climate
variations.
(3) Coping capacity. Finally, if effects are experienced due to a combination
of exposure and sensitivity, how able is a settlement to handle those
impacts without disabling damages, perhaps even with new opportunities?
At the current state of knowledge, vulnerabilities to possible impacts (including
possible opportunities as well as possible costs, despite the negative implications
of the term “vulnerability”) are easier to project than actual impacts because they
estimate risks or opportunities associated with possible consequences rather
than estimating the consequences themselves. And vulnerabilities are shaped
not only by existing exposures, sensitivities, and coping capacities but also by
the ability of settlements to develop adaptive responses to risks (see Adaptation
below).
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Possible impacts of climate change on settlements in the U.S. are usually
assessed by projecting climate changes at a regional scale: temperature,
precipitation, severe weather events, and sea level rise. Ideally, these regional
projections are at a relatively detailed scale, and ideally they consider seasonal
as well as annual changes and changes in extremes as well as in averages; but
these conditions cannot always be met.
The most comprehensive assessments of possible climate change impacts on
settlements in the U.S. have been two studies of major metropolitan areas:
(1) New York: The first U.S. National Assessment of Potential Consequences
of Climate Variability and Change, often referred to as “The National
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Assessment” (NACC, 2000) included twenty “regional assessments,” one
of which was specifically designed to examine possible consequences for
a large metropolitan area: the “Metropolitan East Coast,” essentially the
New York city area (Rosenzweig and Solecki, 2001a; also see
Rosenzweig and Solecki, 2001b, and Solecki and Rosenzweig, 2006).
This assessment concluded that impacts of climate change on this
metropolitan area are likely to primarily negative over the long term, with
potentially significant costs increasing as the magnitude of climate change
increases, although there are substantial uncertainties.
(2) Boston: A later study considered Climate’s Long-term Impacts on Metro
Boston (CLIMB), focused on possible interactions between climate change
and infrastructure systems and services in the Boston area, along with
integrated impact and response strategies (Kirshen, Ruth, Anderson, and
Lakshmanan, 2004; also see Kirshen, Ruth, and Anderson, 2006 and
forthcoming). This study concluded that long-term impacts of climate
change are likely to depend at least as much on behavioral and policy
changes over this period as on temperature and other climate changes.
Other U.S. studies include Seattle (Hoo and Sumitani, 2005) and Los Angeles
(Koteen et al, 2001) (Table 1). Internationally, studies have included several
major metropolitan areas, such as London (London Climate Change Partnership,
2004) and Mexico City (Molina, 2005) as well as possible impacts on smaller
settlements (e.g., AIACC: see www.aiaccproject.org). A relevant historical study
of effects of an urban heat wave in the U.S. is Klinenberg, 2003.
Vulnerabilities of settlements to impacts of climate change vary regionally (see
Box and Vignettes below), but they generally include some or many of the
following impact concerns:
(1) Effects on health. It is well-established that higher temperatures in urban
areas are related to higher concentrations of ozone, which in turn cause
respiratory problems. There is also some evidence that combined effects
of heat stress and air pollution may be greater than simple additive effects
(Patz and Balbus 2001). Moreover, historical data show relationships
between mortalities and temperature extremes (Rozenzweig and Solecki,
2001a). Other health concerns include changes in exposure to water and
food-borne diseases, vector-borne diseases, concentrations of plant
species associated with allergies, and exposures to extreme weather
events such as storms, floods, and fires (see health chapter of SAP 4.6).
(2) Effects on water and other urban infrastructures. Changes in precipitation
patterns may lead to reductions in meltwater, river flows, groundwater
levels, and in coastal areas lead to saline intrusion in rivers and
groundwater, affecting water supply; and warming may increase water
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Table 1. Overview of Integrated Assessments of Climate Impacts and
Adaptation in U.S. Cities
Location:
Coverage:
Water supply
Water Quality
Water Demand
Sea-level Rise
Transportation
Communication
Energy
Public Health
Vector-borne Diseases
Food-borne Diseases
Temperature-related
Mortality
Temperature-related
Morbidity
Air-quality Related
Mortality
Air-quality Related
Morbidity
Oher
Ecosystems
Wetlands
Other (Wldfires)
Urban Forests (Trees and
Vegetation)
Air Quality
Extent of:
Quantitative Analysis
Computer-based
Modeling
Scenario Analysis
Explicit Risk Analysis
Involvement of:
Local Planning Agencies
Local Government
Agencies
Private Industry
Non-profits
Citizens
Identification of:
Adaptation Options
Adaptation Cost
Extent of Integration
Across Systems
Attention to Differential
Impacts (e.g., on
individual types of
businesses, specific subpopulations)
Bloomfield
et al. 1999
Greater Los
Los Angeles
Kooten
et al., 2001
New York
Rosenzweig
et al., 2000
Metropolitan
New York
Kirshen
et al., 2004
Metropolitan
Boston
Hoo and
Sumitani, 2005
Metropolitan
Seattle
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Low
None
Medium
Low
Medium
Low
High
High
Low
None
None
None
None
None
Medium
None
High
Medium
Medium
None
None
None
None
None
High
High
High
High
High
High
None
None
None
None
None
None
None
Low
None
Low
High
Medium
None
None
None
X
X
None
X
X
Medium
X
None
X
X
Low
None
None
Low
Low
Low
Low
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REGIONAL VULNERABILITIES OF SETTLEMENTS TO
IMPACTS OF CLIMATE CHANGE
Region
Metro NE
Larger NE
Mid-Atlantic
Coastal SE
Inland SE
More intense storms,
sea-level rise, flooding, heat
stress
Water shortages,
heat stress,
UH1, economic impacts
Upper Midwest
Lake and river levels, extreme
weather events, health
Inner Midwest
Extreme weather events, health
Major Uncertainties
Storm behavior, precipitation
Ecosystem impacts
Ecosystem impacts
Storm behavior,
coastal land use, sea-level rise
Precipitation change,
development paths
Precipitation change, storm
behavior
Storm behavior
Ecological change, reduced
demand for coal
Water supply, extreme events,
stresses on communities
Reduced snow, water shortages,
fire, tourism
Ecosystem impacts, energy
policy impacts
Precipitation changes, weather
extremes
Precipitation changes, effects
on winter snowpack
Arid Southwest
Water shortages, fire
Development paths,
precipitation changes
California
Water shortages, heat stress
Appalachians
Great Plains
Mountain West
Northwest
Alaska
Hawaii
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Vulnerabilities
Flooding, infrastructures, health,
water supply, sea-level rise
Changes in local landscapes,
tourism, water, energy needs
Multiple stresses
Water shortages, ecosystem
stresses, coastal effects
Effects of warming, vulnerable
populations
Storms and other weather
extremes, freshwater supplies,
health
Temperature and precipitation
changes, infrastructure impacts
Precipitation changes, sea-level
rise
Warming, sea-level rise
Storm behavior, precipitation
change
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demands (Kirshen, 2002; Ruth, Bernier, and Jollands, forthcoming).
Moreover, storms, floods, and other severe weather events may affect
other infrastructures such as sanitation, transportation, supply lines for
food and energy, and communication. Exposed structures such as
bridges and electricity transmission networks are especially vulnerable. In
many cases, infrastructures are interconnected; an impact on one can
also affect others (Kirshen, Ruth, and Anderson, forthcoming). An
example is an interruption in energy supply, which increases heat stress
for vulnerable populations (Ruth, Amato, and Kirshen, 2006).
(3) Effects of severe weather events. Clearly, settlements in risk-prone
regions have reason to be concerned about severe weather events,
ranging from severe storms combined with sea-level rise in coastal areas
to increased risks of fire in drier arid areas. Vulnerabilities may be
especially great for rapidly-growing and/or larger metropolitan areas,
where the potential magnitude of both impacts and coping requirements
could be very large (IPCC, 2001).
(4) Effects on energy requirements. Warming is virtually certain to increase
energy demand in U.S. cities for cooling in buildings while it reduces
demands for heating in buildings (see SAP 4.5). Demands for cooling
during warm periods could jeopardize the reliability of service in some
regions by exceeding the supply capacity, especially during periods of
unusually high temperatures (see Vignette below). Higher temperatures
also affect costs of living and business operation by increasing costs of
climate control in buildings (Amato, Ruth, and Kirshen, 2005; Ruth and
Lin, 2006; Kirshen et al., forthcoming).
(5) Effects on the urban metabolism. An urban area is a living complex
mega-organism, associated with a host of inputs, transformations, and
outputs: heat, energy, materials, and others (Decker et al., 2000). An
example is the Urban Heat Index (UHI), which measures the degree to
which built/paved areas are associated with higher temperatures than
surrounding rural areas (see box: Climate Change Impacts on he Urban
Heat Island Effect (UHI)). Imbalances in the urban metabolism can
aggravate climate change impacts, such as roles of UHI in the formation
of smog in cities.
(6) Effects on economic competitiveness, opportunities, and risks. Climate
change has the potential not only to affect settlements directly but also to
affect them through impacts on other areas linked to their economies at
regional, national, and international scales (Rosenzweig and Solecki,
2006). In addition, it can affect a settlement’s economic base if it is
sensitive to climate, as in areas where settlements are based on
agriculture, forestry,water resources, or tourism (IPCC, 2001).
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VIGNETTES OF VULNERABILITY - I
Alaskan settlements
Human settlements in Alaska are already being exposed to impacts from global warming
(ACIA, 2004), and these impacts are expected to increase. Many coastal communities see
increasing exposure to storms, with significant coastal erosion, and in some cases facilities
are being forced either to relocate or to face increasing risks and costs. Thawing ground is
beginning to destabilize transportation, buildings, and other facilities, posing needs for
rebuilding, with ongoing warming adding to construction and maintenance costs. And
indigenous communities are facing major economic and cultural impacts. One recent
estimate of the value of Alaska’s public infrastructure at risk from climate change set the
value at tens of billions of today’s dollars by 2080, with the replacement of buildings, bridges,
and other structures with long lifetimes having the largest public costs (Larsen et al., 2007).
Coastal SE settlements
Recent hurricanes striking the coast of the U.S. Southeast cannot be attributed clearly to
climate change, but if climate change increases the intensity of storms as projected (IPCC,
2001; Emanuel, 2005) that experience suggests a range of possible impacts. Consider, for
example, the case of Hurricane Katrina (IPCC, forthcoming). In 2005, the city of New
Orleans had a population of about half a million, located on the delta of the Mississippi River
along the U.S. Gulf Coast. Urban development throughout the 20th Century has significantly
increased land use and settlement in areas vulnerable to flooding, and a number of studies
had indicated growing vulnerabilities to storms and flooding. In late August 2005, Hurricane
Katrina moved onto the Louisiana and Mississippi coast with a storm surge, supplemented
by waves, reaching up to 8.5 m above sea level. In New Orleans, the surge reached around
5m, overtopping and breaching sections of the city’s 4.5m defenses, flooding 70 to 80 % of
New Orleans, with 55 % of the city’s properties inundated by more than 1.2 m and maximum
flood depths up to 6 m. 1101 people died in Louisiana, nearly all related to flooding,
concentrated among the poor and elderly. Across the whole region, there were 1.75 million
private insurance claims, costing in excess of $40 billion (Hartwig, 2006), while total
economic costs are projected to be significantly in excess of $100 billion. Katrina also
exhausted the federally backed National Flood Insurance Program (Hunter, 2006), which had
to borrow $20.8 billion from the Government to fund the Katrina residential flood claims. In
New Orleans alone, while flooding of residential structures caused $8-$10 billiion in losses,
$3-6 billion was uninsured. 34,000-35,000 of the flooded homes carried no flood insurance,
including many that were not in a designated flood risk zone (Hartwig, 2006). Six months
after Katrina, it was estimated that the population of New Orleans was 155,000, with the
number projected to rise to 272,000 by September 2008 – 56% of its pre-Katrina level
(McCarthy et al. 2006).
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VIGNETTES OF VULNERABILITY – II
Arid Western settlements
Human settlements in the arid West are affected by climate in a variety of ways, but
perhaps most of all by water scarcity and risks of fire. Clearly, access to water for urban
populations is sensitive to climate, although the region has developed a vast system of
engineered water storage and transport facilities, associated with a very complex set of
water rights laws (NACC, 2001). It is very likely that climate change will reduce winter
snowfall in the West, reducing total runoff – increasing spring runoff while decreasing
summer water flows. Meanwhile, water demands for urban populations, agriculture, and
power supply are expected to increase. If total precipitation decreases or becomes more
variable, extending the kinds of drought that have affected much of the interior West in
recent years, water scarcity will be exacerbated, and increased water withdrawals from
wells could affect aquifer levels and pumping costs. Moreover, drying increases risks of
fire, which have threatened urban areas in California and other Western areas in recent
years. The five-year average of acres burned in the West is more than 5 million, and urban
expansion is increasing the length of the urban-wildlands interface (Morehouse et al.,
2006).
Summer 2006 Heat Wave
In July and August 2006, a severe heat wave spread across the United States, with most
parts of the country recording temperatures well above the average for that time of the
year. For example, temperatures in California were extraordinarily high, setting records as
high as 130 degrees. As many as 225 deaths were reported by press sources, many of
them in major cities such as New York and Chicago. Electric power transformers failed in
several areas, such as St. Louis and Queens New York, causing interruptions of electric
power supply, and some cities reported heat-related damages to water lines and roads. In
many cities, citizens without home air-conditioning sought shelter in public and office
buildings, and city/county health departments expressed particular concern for the elderly,
the young, pregnant women, and individuals in poor health. Although this heat wave
cannot be attributed directly to climate change, it suggests a number of issues for human
settlements in the U.S. as they contemplate a prospect of temperature extremes in the
future that are higher and/or longer-lasting than historical experience.
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12
CLIMATE CHANGE IMPACTS ON THE URBAN HEAT ISLAND EFFECT
(UHI)
Climate change impacts on the Urban Heat Island (UHI) effect will primarily depend upon the
geographic location of a specific city, its urban morphology (i.e. landscape and built-up
characteristics), and areal extent (i.e., overall spatial “footprint”). These factors will mitigate or
exacerbate how the UHI phenomenon (Figure 2) is affected by climate change, but overall,
climate change will most likely impact the UHI effect in the following ways:
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Figure 2. Example of urban surface temperatures and albedo for the Atlanta, Georgia
Central Business District (CBD) area derived from high spatial resolution (10m) aircraft
thermal remote sensing data. The image on the left illustrates daytime surface heating for
urban surfaces across the CBD. White and red colors indicate very warm surfaces (~4050oC). Green relates to surfaces of moderately warm temperatures (~25-30oC). Blue
indicates cool surfaces (e.g., vegetation, shadows) (~15-20oC). Surface temperatures are
reflected in the albedo image on the right where warm surfaces are dark (i.e., low
reflectivity) and cooler surfaces are in red and green (i.e., higher reflectivity). The images
exemplify how urban surface characteristics influence temperature and albedo as drivers
of the urban heat island effect (Quattrochi et al., 2000).
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
Exacerbation of the intensity and areal extent of the UHI as a result of warmer surface and air
temperatures along with the overall growth of urban areas around the world. Additionally, as
urban areas grow and expand, there is a propensity for lower albedos which forces more a
more intense UHI effect. (There is also some indication that sustained or prolonged higher
nighttime air temperatures over cities that may result from warmer global temperatures will
have a more significant impact on humans than higher daytime temperatures.)

As the UHI intensifies and increases, there will potentially be a subsequent impact on
deterioration of air quality, particularly on ground level ozone caused by higher overall air
temperatures and an increased background effect produced by the UHI as an additive air
temperature factor that helps to elevate ground level ozone production. Additionally,
particulate matter (PM2.5) will potentially increase due to a number of human induced and
natural factors (e.g., more energy production to support higher usage of air conditioning).
-
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CLIMATE CHANGE IMPACTS ON THE URBAN HEAT ISLAND EFFECT
(UHI)structures.
-- continuedClimate change can add to
(7) Effects on social and political
stress on social and political structures by increasing management and
 The UHI
has requirements
an impact on local
meteorological
by forcing
rainfall
budget
for public
servicesconditions
such as public
health
care,
production
either
over,
or
downwind,
of
cities.
As
the
UHI
effect
intensifies,
disaster risk reduction, and even public security. As sources of there
stresswill
be a grow
higherand
probability
for
urban-induced
rainfall
production
(dependent
upon
combine, the resilience of social and political structures that are
geographic location) with a subsequent increase in urban runoff and flash flooding.
already somewhat shaky is likely to suffer, especially in areas with
relatively limited resources (Sherbinin et al., 2006).Especially vulnerable
 Exacerbation and intensification of the UHI will have impacts on human health:
populations (also see Quality of Life chapter of SAP 4.6). Where climate
change
adds toincidence
stress levels
in stress
settlements, it is likely to be especially
- increased
of heat
problematic
for respiratory
vulnerableillnesses
parts ofsuch
the population:
thetopoor,
the elderly,
- impact on
as asthma due
increases
in
thoseparticulate
already inmatter
poor health,
disabled, those
caused the
by deterioration
in airliving
qualityalone,
as wellthose
as with
limitedincreased
rights and
pollination
power (e.g.,
production
recent
because
in-migrants
of earlier
withpollen
limited
production
English from
in responsepopulations
to warmer overall
temperatures
skills),vegetation
and/or indigenous
dependent
on one or a few
resources. As one example, warmer temperatures in urban summers
have a more direct impact on populations who live and work without air(Ridd,
2006; Brazel and
Quattrochi,
Lo and Quattrochi,
2003;
Stone,
2006)
conditioning.
Implications
for2006;
environmental
justice are
clear;
see,
for
instance, Congressional Black Caucus Foundation, 2004.
(7) Effects on social and political structures. Climate change can add to
stress on social and political structures by increasing management and
budget requirements for public services such as public health care,
disaster risk reducttion, and even public security. As sources of stress
grow and combine, the resilience of social and political structures that are
already somewhat shaky is likely to suffer, especially in areas with
relatively limited resources (Sherbinin et al., 2006). Especially vulnerable
populations (also see Quality of Life chapter of SAP 4.6). Where climate
change adds to stress levels in settlements, it is likely to be especially
problematic for vulnerable parts of the population: the poor, the elderly,
those already in poor health, the disabled, those living alone, those with
limited rights and power (e.g., recent in-migrants with limited English
skills), and/or indigenous populations dependent on one or a few
resources. As one example, warmer temperatures in urban summers
have a more direct impact on populations who live and work without airconditioning. Implications for environmental justice are clear; see, for
instance, Congressional Black Caucus Foundation, 2004.
(8) Effects of sea level rise. Approximately half of the U.S. population, 160
million people, will live in one of 673 coastal counties by 2008 (NOAA,
2005). Obviously, settlements in coastal areas – particularly on gentlysloping coasts – should be concerned about sea level rise in the longer
term, especially if they are subject to severe storms and storm surges
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and/or if their regions are showing gradual land subsidence (Neuman et
al., 2000; Kirshen et al., 2004).
In general, however, climate change effects on human settlements in the U.S.
are imbedded in a variety of complexities that make projections of quantitative
impacts over long periods of time very difficult. For instance, looking out over a
period of many decades, it seems likely that other kinds of change – such as
technological, economic, and institutional – will have more impact on the
sustainability of most settlements than climate change per se (IPCC,
forthcoming). Climate change will interact with other processes, driving forces,
and stresses; and its significance, positive or negative, will largely be determined
by these interactions. It is therefore difficult to assess effects of climate change
without a reasonably clear picture of future scenarios for these other processes,
which are usually not available.
In many cases, these interactions involve not only direct impacts such as
warming or more or less precipitation but, sometimes more important, second,
third, etc. order impacts, as direct impacts cascade through urban systems and
processes (e.g., warming which affects urban air pollution which affects health
which affects public service requirements which affects social harmony: Kirshen
et al, forthcoming). Some of these higher-order impacts, in turn, may feed back
to create ripple effects of their own. For example, a heat wave may trigger
increased energy demands for cooling, which may cause more air conditioners
and power generators to be operated, which could lead to higher urban heat
island effects, inducing even higher cooling needs.
Besides such a “multi-stress” perspective, it is highly likely that effects of climate
change on settlements is shaped by certain “thresholds,” below which effects are
not major but where effects rather quickly become major because some kind of
limiting point is reached. An example might be a city’s capacity to cope with
sustained heat stress of with a natural disaster. In general, these climate-related
thresholds for human settlements in the U.S. are not well-understood.
But for either multi-stress assessments of threshold analyses, changes in climate
extremes are very often of more concern than changes in climate averages.
Besides extreme weather events, such as hurricanes or tornadoes, ice storms,
winds, heat waves, drought, or fire, settlements may be affected by changes in
daily or seasonal high or low levels of temperature or precipitation, which are
seldom projected by climate change models (see Figure 1).
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Finally, human settlements may be affected by climate change mitigation
initiatives as well as by climate change itself. Examples could include effects on
policies related to energy sources and uses, environmental emissions, and land
use (see Adaptation below). The most direct and short-term effects would likely
be on settlements in regions whose economies are closely related to the
production and consumption of large quantities of fossil fuels. Indirect and longer
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Figure 1. The U.S. National Assessment (NACC, 2001) projected changes in the
July heat index for regions of the U.S. For the already hot and humid Southeast,
for instance, the UK Hadley model suggested increases of 8 to 15 degrees F. for
the southern-most states, while the Canadian model projected increases above 20
degrees for much of the region.
term effects are less predictable . At the same time, climate change can have
positive as well as negative implications for settlements. Examples of possible
positive effects include:
(1) Reduced winter weather costs and stresses. Warmer temperatures in
periods of the year that are normally cold are not necessarily undesirable.
They reduce cold-related stresses and costs (e.g., costs of warming
buildings and costs of clearing ice and snow from roads and streets),
particularly for cold-vulnerable populations. They expand opportunities
for warmer-weather recreational opportunities over larger parts of the
year, and they expand growing seasons for crops, parks, and gardens.
(2) Increased attention to long-term sustainability. One of the most positive
aspects of a concern with climate change can be that it stimulates a
broader discussion of what sustainability means for a city or smaller
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settlement (Wilbanks, 2003; Ruth, 2006). Even if climate change itself
may not be the most serious threat to sustainability, considering climate
change impacts in a multi-change, multi-stage context can encourage and
facilitate processes that lead to progress in dealing with other sources of
stress as well.
(3) Improved competitiveness compared with settlements subject to more
serious adverse impacts. While some settlements may turn out to be
“losers” due to climate change impacts, for instance related to perceptions
of increased storm risks or effects on tourism, others may be “winners,” as
changes in temperature or precipitation result in added economic
opportunities (see the following section). In addition for many settlements
climate change can be an opportunity not only to compare their net
impacts with others, seeking advantages as a result, but to present a
progressive image by taking climate change (and related sustainability
issues) seriously. Examples might include cities in the border south who
try to persuade prospective sun-belt retirees that locations farther south,
especially in coastal locations, could be too hot or too storm-prone to be
good places to move, or settlements in some sections of the northern part
of the country who make a case that reduced costs for winter heating are
greater than increased costs for summer cooling.
Possible effects on U.S. settlement patterns and characteristics
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As climate change affects individual settlements in the U.S., large and small,
those changes are likely to have effects on population patterns involving hosts of
settlements at regional and national scales, in combination with other driving
forces (even if other forces are often more important, such as demographic
changes). Most of the possible effects are linked with changes in regional
comparative advantage, with consequent migration of population and economic
activities (Ruth and Coelho, forthcoming).
Examples of such possible issues include:
(1) Particular regional risks. It is likely that regions exposed to risks from
climate change will see a movement of population growth and economic
activity to other locations. One reason is public perceptions of risk, but a
more powerful driving force may be the availability of insurance. The
insurance sector is one of the most adaptable of all economic sectors, and
its exposure to costs from severe storms and other extreme weather
events is likely to lead it to withdraw (or to make much more expensive)
private insurance coverage from areas vulnerable to climate change
impacts (IPCC, forthcoming), which would encourage both businesses
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and individual citizens to consider other locations over a period of several
decades.
(2) Areas whose economies are linked with climate-sensitive resources or
assets. Settlements whose economic bases are related to such sectors
as agriculture, forestry, tourism, water availability, or other climate-related
activities could be affected either positively or negatively by climate
change, depending partly on the adaptability of those sectors (i.e., their
ability to adapt to changes without shifting to different locations).
(3) Shifts in the comparative cost structure of climate control. Related to a
range of possible climate change effects – higher costs for space cooling
in warmer areas, higher costs of water availability in drier areas, more or
less exposure to storm impacts in some areas, and sea level rise –
regions of the U.S. and their associated settlements are likely to see
gradual changes over the long term in their relative attractiveness for a
variety of human activities. One example, although its likelihood is highly
uncertain, would be a gradual migration of the “Sun Belt” northward, as
retirees and businesses attracted by environmental amenities find that
regions less exposed to very high temperatures and seasonal major
storms are more attractive as places to locate.
(4) Changes in regional comparative advantage related to shifts in energy
resource use. If climate mitigation policies result in shifts from coal and
other fossil resources toward non-fossil energy sources, or if climate
changes affect the prospects of renewable energy sources (especially
hydropower), regional economies related to the production and/or use of
energy from these sources could be affected, along with regional
economies more closely linked with alternatives.
(5) Urban “footprints” on other areas. Resource requirements for urban areas
involve larger areas than their own bounded territories alone, and
ecologists have sought to estimate the land area required to supply the
consumption of resources and compensate for emissions and other
wastes from urban areas (e.g., Folke, et al., 1997). By possibly affecting
the sizes and patterns of settlements, along with the resource capacities
of source areas for their inputs and destinations of their outputs, climate
change could affect the nature, size, and geographic distribution of these
footprints.
As one example, no other region in the U.S. is likely to be as profoundly changed
by climate change as Alaska, our nation’s part of the polar region of Earth.
Because warming is more pronounced closer to the poles, and because
settlement and economic activities in Alaska have been shaped and often
constrained by Arctic conditions, in this region warming is especially likely to
reshape patterns of human settlement.
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Besides impacts on built infrastructures designed for permafrost foundations and
effects on indigenous societies (see Vignette above), many observers expect
warming in Alaska to stimulate more active oil and gas development (and
perhaps other natural resource exploitation), and if thawing of Arctic ice permits
the opening of a year-round Northwest sea passage it is virtually certain that
Alaska’s coast will see a boom in settlements and port facilities (ACIA, 2004).
Possible effects on other systems linked with settlements
Human settlements are foci for many economic, social, and governmental
processes, and we know from historical experience that catastrophes in cities
can have significant economic, financial, and political effects much more broadly.
The case which has received the most attention to date is insurance and finance
(IPCC, forthcoming). Other cases of possible ripple effects are on media and
other information/communications sources, often city-focused, whose messages
are affected by the personal experiences of those who are their purveyors.
Most importantly, perhaps, in a one-person/one-vote democratic process in an
urbanizing country, the politics of responses to climate change concerns will
depend considerably on the experiences and viewpoints of urban dwellers.
Potentials for Adaptation to Climate Change in Human
Settlements
Settlements are important in considering prospects for adaptation to climate
change, both because they represent concentrations of people and because
buildings and other engineered infrastructures are ways to manage risk and
monitor/control threats associated with climate extremes and other effects, such
as disease vectors.
Where climate change might present risks of adverse impacts for U.S.
settlements and their populations, there are two basic alternatives to respond to
such concerns (a third is combining the two). One response is to contribute to
climate change mitigation strategies, i.e., by taking actions to reduce their
greenhouse gas emissions and by showing leadership in encouraging others to
support such actions (see Box: Roles of Settlements in Climate Change
Mitigation). The second response is to consider strategies for adaptation to the
changes, i.e., finding ways either to reduce sensitivity to projected changes or to
increase the settlement’s coping capacities. Adaptation can rely mainly on
anticipatory actions to avoid damages and costs, such as “hardening” coastal
structures to sea-level rise; and/or adaptation can rely mainly on response
potentials, such as emergency preparedness; or it can include a mix of the two
approaches. Research to date suggests that reactive adaptation may be less
cost-effective than anticipatory adaptation (Kirshen et al., 2004).
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Adaptation could be important to the well-being of U.S. settlements as climate
change emerges over the next century. As just one example, the New York
climate impact assessment (Rosenzweig and Solecki, 2001a) projects significant
increases in heat-related deaths based on historical relationships between heat
stress and mortality, while the Boston CLIMB assessment (Kirshen et al., 2004)
projects that, despite similar projections of warming, heat-related deaths will
decline over the coming century because of adaptation. Whether or not
adaptation to climate change occurs in U.S. cities is therefore a potentially very
serious issue. The CLIMB assessment includes analyses showing that in many
cases adaptation actions taken now are better than adaptation actions delayed
until a later time (Kirshen et al., 2006).
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Perspectives on adaptation by settlements
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In most cases, for decision-makers in U.S. settlements considering climate
change as yet one more source of possible risks and stress while they wrestle
with a host of challenges every day. For them, climate change is different as an
issue because it is relatively long-term in its implications, future impacts are
surrounded by uncertainties, and public awareness is growing from a relatively
low level to a higher level of concern. Because climate change is different in
these ways, it is seldom attractive to consider allocating massive amounts of
funding or management attention to current climate change actions for that
reason alone. What generally makes more sense is to consider ways that
actions which reduce vulnerabilities to climate change impacts (or increase
prospects for realizing benefits from climate change impacts) are also desirable
for other reasons as well: often referred to as “co-benefits.” Examples include
actions that reduce vulnerabilities to current climate variability regardless of longterm climate change, actions that add resilience to water supply and other urban
infrastructures that are already stressed, and actions that make metropolitan
areas more attractive for their citizens in terms of their overall quality of life.
Human settlements have used both ”hard” approaches such as infrastructure and
“soft” approaches such as regulations to capture services or protection from
their climate and their environment. Examples include water supply and waste
water systems, drainage networks, buildings, transportation systems, land use
and zoning controls, water quality standards and emission caps, and tax
incentives. All of these are designed in part with climate and environmental
conditions in mind. The setting of regulations has always been a context of
benefit-cost analysis and political realities; and infrastructure is also designed in
a benefit-cost framework, subject to local design codes. The fact that both
regulations and infrastructures vary considerably across the U.S. reflects cultural,
economic, and environmental factors; and this suggests that mechanisms exist to
respond to concerns about climate change. Urban designers and managers deal
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routinely with uncertainties, because they must consider uncertain demographic
and other changes; thus, if climate change is properly institutionalized into the
urban planning process, it can just be handled as yet another uncertainty.
4
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Major categories of adaptation options
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Adaptation strategies for human settlements, large and small, include a wide
range of possibilities such as:
- Changing the location of people or activities (within or between settlements) –
especially addressing the costs of sustaining built environments in vulnerable
areas: e.g., siting and land use policies practices to shift from more vulnerable
areas to less, adding resilience to new construction in vulnerable areas,
increased awareness of changing hazards and associated risks, assistance for
the less-advantaged (including actions by the private insurance sector as a likely
driving force).
- Changing the spatial form of a settlement – managing growth and change over
decades without excluding critical functions (e.g., architectural innovations
improving the sustainability of structures, reducing transportation emissions by
reducing the length of journeys to work, seeking efficiencies in resource use
through integration of functions, and moving from brown spaces to green
spaces). Among the alternatives receiving the most attention are encouraging
“green buildings”(e.g., green roofs: Parris, 2007; see Rosenzweig, Gaffin, and
Paarshall, 2006, and Rosenzweig, Solecki, and Slosberg, 2006) and increasing
“green spaces” within urban areas (e.g., Bonsignore, 2003).
- Technological change to reduce sensitivity of physical and linkage
infrastructures – e.g., more efficient and affordable interior climate control,
surface materials that reduce heat island effects (Quattrochi et al., 2000), waster
reduction and advanced waste treatment, better warning systems and controls.
- Institutional change to improve coping capacity, including assuring effective
governance, providing financial mechanisms for increasing resiliency, improving
structures for coordinating among multiple jurisdictions, targeting assistance
programs for especially impacted segments of the population, and adopting
sustainable community development practices (Wilbanks et al., 2007). Policy
instruments include zoning, building and design codes, terms for financing, and
early warning systems (Kirshen, Ruth, and Anderson, 2005).
-“No regrets” or low net cost policy initiatives that add resilience to the settlement
and its physical capital – e.g., in coastal areas changing building codes for new
construction to require coping with projected amounts of sea-level rise over the
expected lifetimes of the structures.
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The choice of strategies from among the options is likely to depend on “cobenefits” in terms of other social, economic, and ecological driving forces; the
availability of fiscal and human resources; and political aspects of “who wins” and
“who loses”.
7
Current considerations of adaptation strategies
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In most cases to date in the U.S., settlements have been more active in climate
change mitigation than climate change adaptation (see box), but there are some
indications that adaptation is growing as a subject of interest (Solecki and
Rosenzweig, 2005; Ruth, 2006). For example, Boston has built a new
wastewater treatment plant at least one-half meter higher than currently
necessary to cope with sea level rise, and in a coastal flood protection plan for a
site north of Boston the U.S. Corps of Engineers incorporated sea-level rise into
their analysis (Easterling, Hurd, and Smith, 2004). California is considering
climate change adaptation strategies as a part of its more comprehensive
attention to climate change policies (Franco, 2005). And, of course, Alaska is
already pursuing ways to adapt to permafrost melting and other climate change
effects.
Meanwhile, in some cases settlements are taking actions for other reasons that
add resilience to climate change effects. An example is the promotion of water
conservation, which is reducing per capita water consumption in cities that could
be subject to increased water scarcity (City of New York, 2005).
It seems very likely that local government will play an important role in climate
change responses in the U.S. Many adaptation options must be evaluated at a
relatively local scale in terms of their relative costs and benefits and their
relationships with other urban sustainability issues, and local governments are
important as guardians of public services, able to mobilize a wide range of
stakeholders to contribute to broad community-based initiatives (as in the case of
the London Climate Change Partnership, 2004). Because climate change impact
concerns and adaptation potentials tend to cross jurisdictional boundaries in
highly fragmented metropolitan areas, local actions might encourage crossboundary interactions that would have value for other reasons as well.
While no U.S. communities have developed comprehensive programs to mitigate
the effects of heat islands, some localities are recognizing the need to address
these effects. In Chicago, for example, several municipal buildings have been
designed to accommodate vegetated rooftops. Atlanta has had a Cool
Communities “grass roots” effort to educate local and state officials and
developers on strategies that can be used to mitigate the UHI. This Cool
Communities effort was instrumental in getting the State of Georgia to adopt the
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first commercial building code in the country emphasizing the benefits of cool
roofing technology (Young, 2002; Estes, Jr., et al., 2003).
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Alternatives for enhancing adaptation capacities
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In most cases, the likelihood of effective adaptation is related to the capacity to
adapt, which in turn is related to such variables as knowledge and awareness,
access to fiscal and human resources, and good governance (IPCC, 2001).
Strategies for enhancing such capacities in U.S. settlements are likely to include
the development and use of local expertise on climate change issues (AAG,
2003), attention to the emerging experience with climate change effects and
response strategies globally and in other U.S. settlements, information sharing
about adaptation potentials and constraints among settlements and their
components (likely aided by modern information technology), and an emphasis
on participatory decision-making, where local industries, institutions, and
community groups are drawn into discussions of possible responses.
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Conclusions and Recommendations
Even from a current knowledge base that is very limited, it is possible to conclude
several things about effects of climate change on human settlements in the
United States:
(1) Climate change will seldom be a primary factor in an area’s development
compared with other driving forces for development. It is likely to be a
secondary factor, with its importance determined mainly by its interactions
with other factors, except in the case of major abrupt climate change (very
likely).
(2) Effects of climate change will vary considerably according to locationspecific vulnerabilities, and the most vulnerable areas are likely to be
Alaska, coastal and river basin locations susceptible to flooding, arid
areas where water scarcity is a pressing issue, and areas whose
economic bases are climate-sensitive (very likely).
(3) Except for Alaska, the main impact concerns have to do with changes in
the intensity, frequency, and/or location of extreme weather events and, in
some cases, water availability rather than changes in temperature (very
likely).
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ROLES OF SETTLEMENTS IN CLIMATE CHANGE MITIGATION
Although the US government has not committed itself to climate change mitigation policies at the
national level, an astonishing number of state and local authorities are actively involved in
considerations of how to mitigate greenhouse gas emissions (Selin and Vandeveer 2005, Rabe
2006 and Selin 2006). US states and cities are joining such initiatives as ICLEI (217 U.S. local
government members: ICLEI, 2006), the US Mayor Climate Protection Agreement (10 mayors),
the Climate Change Action Plan, the Regional Greenhouse Gas Initiative (RGGI) (Selin 2006), and
the Large Cities Climate Leadership Group (3 large cities).() Those initiatives focus on emissions
inventories; on such actions aimed at reducing GHG emissions as switching to more energy
efficient vehicles, using more efficient furnaces and conditioning systems, and introducing
renewable portfolio standards (RPS), which mandate a formal increase in the amount of electricity
generated from renewable resources; on measures to adapt to negative social, economic and
environmental impacts; and on actions to promote public awareness (see references in footnote
1).
Different drivers lie behind these mitigation actions. Authorities and the population at large have
begun to “perceive” such possible impacts of climate change as rising sea level, extreme shifts in
weather, and losses of key resources. They have realized that a reduction of GHG emissions
opens opportunities for longer economic development (e.g. investment in renewable energy:
Rabe 2006). In addition, climate change can become a political priority if it is reframed in terms of
local issues (i.e. air quality, energy conservation) already in the policy agenda (Betsill 2001,
Bulkeley and Betsill 2003, Romero Lankao 2007)
The promoters of these initiatives face challenges related partly to inertia (e.g. the time it takes to
replace energy facilities and equipment with a relatively long life of 5 to 50 years: Haites et al
2007). They can also face opposition from organizations who do not favor actions to reduce GHG
emissions, some of whom are prepared to bring legal challenges against state and local initiatives
(Rabe 2006: 17). But the number of bottom-up grassroots activities currently under way in the US
is impressive, and that number appears to be growing.
ICLEI is the International Council for Local Environmental Initiatives. Local governments participating in ICLEI’s Cities
for Climate Protection (CCP) Campaign commit to a) conduct an energy- and emissions-inventory and forecast, b)
establish an emissions target, c) develop and obtain approval for the Local Action Plan, d) Implement policies and
measures, and e) monitor and verify results (ICLEI 2006: April 20 2006 www.icle.org). The Large Cities Climate
Leadership Group is a group of cities committed to the reduction of urban carbon emissions and adapting to climate
change. It was founded following the World Cities Leadership Climate Change Summit organized by the Mayor of
London in October 2005. For more information on the US Mayor Climate Protection Agreement see
http://www.seattle.gov/mayor/climate/
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(4) Over the time period covered by climate change projections, potentials for
adaptation through technological and institutional development as well as
behavioral changes are considerable, especially where such
developments meet other sustainable development needs as well,
especially considering the initiatives already being shown at the local level
across the U.S. (extremely likely).
(5) While uncertainties are very large about specific impacts in specific time
periods, it is possible to talk with a higher level of confidence about
vulnerabilities to impacts for most settlements in most parts of the U.S.
(virtually certain).
(6) Clarifying these vulnerabilities and reducing uncertainties about impacts
would benefit from a higher level of effort in impact research (virtually
certain).
(7) Promoting climate change mitigation and adaptation discussions at an
urban/settlement scale will benefit from involvement of stakeholders
(virtually certain).
Based on this first preliminary assessment, it is recommended that:
(1) Research on climate change effects on human settlements in the U.S.,
especially major metropolitan areas, be given a much higher priority in
order to inform metropolitan-area scale decision-making.
(2) In particular, in-depth case studies of selected urban area impacts and
responses be added without extended delay. Priorities include coastal
areas of the Southeast, interior areas of the Southeast, arid areas of the
Southwest, coastal areas of the Northwest, and the Great Lakes region of
the Midwest.
(3) In these and other studies of climate impacts and responses in human
settlements, stakeholders be explicitly involved in order to access their
knowledge bases and inform their responses.
(4) Organizations who represent urban area decision-making in the U.S. be
encouraged to engage more actively in discussions of climate change
impact and response issues.
(5) Responsibility be assigned to one U.S. government agency to lead the
national effort to improve information about climate change vulnerabilities,
impacts, and responses for the nation’s cities and smaller settlement.
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(6) In all of these connections, a structure and a process be established for
informing U.S. urban decision-makers about what climate change effects
might mean for their cities, how to integrate climate change considerations
into what they do with building codes, zoning, lending practices, etc. as
mainstreamed urban decision processes.
(7) Structures be developed and supported over the long term to document
experiences with urban/settlement climate change responses and provide
information about these experiences to decision-making, research, and
stakeholder communities.
Research Needs
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According to a number of sources, including NACC, 1998; Parson et al., 2003;
Ruth, 2006; and Ruth, Donaghy, and Kirshen, 2004, research needs for
improving the understanding of effects of climate change on human settlements
in the United States include:
(1) Increasing the number of case studies of settlement vulnerabilities,
impacts, and adaptive responses in a variety of different local contexts
around the country.
(2) Developing better projections of climate change at the scale of U.S.
metropolitan areas or smaller, including scenarios projecting extremes and
scenarios involving abrupt changes.
(3) Developing realistic, socially acceptable strategies for shifting human
populations and activities away from vulnerable locations.
(4) Improving the understanding of vulnerable populations within and among
urban areas: populations with limited capacities for response, limited
ability to affect major decisions.
(5) Improving the understanding of how urban decision-making is changing as
populations become more heterogeneous and decisions become more
decentralized and “democratic,” especially as this affects adaptive
responses.
(6) Improving abilities to associate projections of climate change in U.S.
settlements with changes in other driving forces related to impacts, such
as changes in metropolitan/urban patterns and technological change.
(7) Improving the understanding of relationships between settlement patterns
(both regional and intra-urban) and resilience/adaptation.
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(8) Considering possible impact thresholds and what they depend upon.
(9) Improving the understanding of vulnerabilities of urban inflows and
outflows to climate change impacts.
(10) Improving the understanding of second and third-order impacts of
climate change in urban environments, including interaction effects among
different aspects of the urban system.
(11) Reviewing current regulations, guidelines, and practices related to
climate change responses to help inform community decision-makers and
other stakeholders about potentials for relatively small changes to make a
large difference.
Meeting these needs is likely to require a rich partnership between the federal
government, state and local governments, industry, non-governmental
organizations, foundations, and academia, both because the federal government
will have only limited resources to invest in such research and because the
research effort will benefit from full participation by all.
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References
Amato, A., M. Ruth, P. Kirshen and J. Horwitz. 2005: Regional energy demand
responses to climate change: Methodology and application to the
Commonwealth of Massachusetts, Climatic Change, 71(1), 175 – 201.
ACIA, 2004: Arctic Climate Impact Assessment: Impacts of a Warming Arctic:
Arctic Climate Impact Assessment, Cambridge University Press, Cambridge.
AIACC: Assessments of Impacts and Adaptations to Climate Change in Multiple
Regions and Sectors. Accessed 01/25/2007 at: http://www.aiaccproject.org
Association of American Geographers, 2003: Global Change In Local Places:
Estimating, Understanding, And Reducing Greenhouse Gases, [GCLP
Research Team: Kates, R., T. Wilbanks, and R. Abler (eds.)]. Association of
American Geographers, Cambridge University Press, Cambridge, MA.
Betsill, M.M. 2001: Mitigating climate change in US cities: Opportunities and
obstacles, Local Environment , 4:393-406.
Bloomfield, J., M. Smith and N. Thompson, 1999, Hot Nights in the City: Global
Warming, Sea-Level Rise and the New York Metropolitan Region,
Environmental Defense Fund , Washington, D.C.
Brazel, A.J. and D.A. Quattrochi, 2005: “Urban Climates”. In Encyclopedia of
World Climatology. [J.E. Oliver, (ed.)]. Springer, Dordrecht, The
Netherlands: 766-779.
Bulkeley, H. and M. Betsill, 2003: Cities and Climate Change; Urban
Sustainability and Global Environmental Governance. London, Routledge.
City of New York, 2005: New York City's Water Supply System, The City of
New York Department of Environmental Protection, New York.
Clark, W. C., et al., 2000: Assessing Vulnerability to Global Environmental
Risks, Discussion Paper 200-12, Environment and Natural Resources
Program, Kennedy School of Government. Harvard University, Cambridge:.
Congressional Black Caucus Foundation, 2004: African Americans and
Climate Change: An Unequal Burden. Redefining Progress.
Washington:
Decker, E., S. Elliot, F. Smith, D. Blake, and F. Rowland, 2000: Energy and
material flow through the urban ecosystem, Annual Review of Energy and
the Environment, 25: 685-740.
28
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
Emanuel, K. A., 2005: Increasing destructiveness of tropical cyclones over the
past 30 years, Nature, 436, 686-688.
Estes, M, D. Jr., D. Quattrochi, and E. Stasiak, 2003: The urban heat island
phenomena: How Its effect can influence environmental decision making in
your community, Public Management, 85:8-12.
Folke, C., A. Janssen, J. Larsson, and R. Costanza, 1997: Ecosystem
appropriation by cities, Ambio, 26:167-172.
Haites, E., K. Caldeira, P. Romero Lankao, A. Rose, and T. Wilbanks, 2007:
What are the options that could significantly affect the carbon cycle?, U.S.
Climate Change Science Program Synthesis and Assessment Product 2.2.,
State of the Carbon Cycle Report (SOCCR), (in review)
Hartwig, R., 2006: Hurricane Season Of 2005, Impacts On U.S. P/C Markets,
2006 And Beyond, Presentation to the Insurance Information Institute, New
York, NY. Accessed on 17 April 2006 at
http://www.iii.org/media/presentations/katrina/
Hoo, W. and M. Sumitani, 2005: Climate Change Will Impact the Seattle
Department of Transportation, Seattle, Washington, Office of the City Auditor
ICLEI, 2006: http://www.iclei.org
IPCC, 2001a: Human settlements, energy, and industry In: IPCC 2001b
IPCC, 2001b: Climate Change 2001: Impacts, Adaptation, and Vulnerability.
Cambridge University Press, Cambridge, 967 pp.
IPCC, 2001c: Insurance and other financial services. In: IPCC 2001b
IPCC, forthcoming. “Industry, Settlement, and Society.” Intergovernmental
Panel on Climate Change (IPCC), Working Group II, Fourth Assessment
Report, Chapter 7. (not for citation before WG II Plenary, April 2-6, 2007, but
can be cited after that)
Kirshen, P. H., 2002: Potential impacts of global warming in eastern
Massachusetts. Journal of Water Resources Planning and Management, ASCE
128, 3: 216-226.
29
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
Kirshen, P.H., M. Ruth, W. Anderson, T. R. Lakshmanan, S. Chapra, W.
Chudyk, L. Edgers, D. Gute, M. Sanayei and R. Vogel, 2004: Climate's
Long-term Impacts on Metro Boston, Final Report to the U.S. Environmental
Protection Agency, Office of Research and Development, Washington, D.C.
Kirshen, P., M. Ruth, and W. Anderson, 2006: Climate’s long-term impacts on
urban infrastructures and services: The case of metro Boston, [M. Ruth, P.
Kirshen, and Donaghy, (eds)], Climate Change and Variability: Impacts and
Responses, Edward Elgar, Cheltenham, UK, 190-252.
Kirshen, P., M. Ruth, and W. Anderson, forthcoming: Interdependencies of
urban climate change impacts and adaptation strategies: A case study of
metropolitan Boston,” Climatic Change.
Klinenberg, E., 2003. Heat Wave: A Social Autopsy of Disaster in Chicago,
University of Chicago, Chicago
Koteen, L., J. Bloomfield, T. Eichler, C. Tonne, R. Young, H. Poulshock and A.
Sosler, 2001: Hot Prospects: The Potential Impacts of Global Warming on
Los Angeles and the Southland, Environmental Defense, Washington, D.C.,
Larsen, Peter; O. S. Goldsmith; O. Smith and M. Wilson 2007: A Probabilistic
Model to Estimate the Value of Alaska Public Infrastructure at Risk to Climate
Change (PDF). ). ISER Working Paper, Institute of Social and Economic
Research, University of Alaska, Anchorage..
Lo, C.P. and D.A. Quattrochi, 2003: Land-use and land-cover change, urban
heat island phenomenon, and health implications: A remote sensing
approach, Photogrammetric Engineering and Remote Sensing,
London Climate Change Partnership, 2004: London’s Warming, A Climate
Change Impacts in London Evaluation Study, London, 293 pp
McCarthy, K., D. Peterson, N. Sastry, and M. Pollard, 2006: The Repopulation
of New Orleans after Hurricane Katrina, Rand, Santa Monica, CA
Molina, M. et al., 2005: Air Quality in the Mexico Megacity: An Integrated
Assessment, Kluwer, Dordrecht, Netherlands
NACC, 2000: Climate Change Impacts on the United States: The Potential
Consequences of Climate Variability and Change, U.S. Global Change
Research Program, Washington
30
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
Neumann, J.E., G. Yohe, R. Nichols, and M. Manion, 2000: Sea Level Rise and
Global Climate Change: A Review of Impacts to U.S. Coasts, Pew Center on
Global Climate Change, Washington DC.
23
24
25
26
Ridd, M.K., 2006: “10.3 Environmental Dynamics of Human Settlements”. [In
Remote Sensing of Human Settlements. Manual of Remote Sensing, Third
Editions, Volume 5 (M.K. Ridd and J.D. Ripple, eds)], American Society for
Photogrammetry and Remote Sensing, Bethesda, MD: 564-642.
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
NOAA, 2005. Population Trends Along the Coastal United States, 1980-2008.
http://www.oceanservice.noaa.gov/programs/mb/supp_cstl_population.html
Parris, T., 2007: Green buildings, Environment, 49/1: 3.
Patz, J. A. and J. M. Balbus, 2001: Global climate change and air pollution. [In:
Aron J. L. , J. A. Patz (eds)], Ecosystem Change And Public Health. A
Global Perspective. The Johns Hopkins University Press, Baltimore, pp 379–
408
Quattrochi, D.A., J.C. Luvall, D.L. Rickman, M.G. Estes, Jr., C.A. Laymon, and
B.F. Howell, 2000: A decision support system for urban landscape
management using thermal infrared data, Photogrammetric Engineering
and Remote Sensing 66:1195-1207.
Rabe, B., Second Generation Climate Policies in the States, paper presented at
the Conference Climate Change Politics in North America, Washington DC,
May 18-19 2006, http://www.wilsoncenter.org/ecsp.
Romero Lankao, P., 2007: Are we missing the point? Particularities of
urbanization, sustainability and carbon emissions in Latin American cities,
Urbanization and Environment, 19(1) (in press)
Rosenzweig, C., W. Solecki, C. Paine, V. Gornitz, E. Hartig, K. Jacob, D. Major,
P. Kinney, D. Hill and R. Zimmerman, 2000: Climate Change and a Global
City: An Assessment of the Metropolitan East Coast Region, U.S. Global
Change Research Program. Acessed January 19, 2007 at
http://metroeast_climate.ciesin.columbia.edu
Rosenzweig, C., and W. Solecki, eds. 2001a: Climate Change and a Global
City: The Potential Consequences of Climate Variability and Change –
Metro East Coast, New York: Columbia Earth Institute.
Rosenzweig, C. and W.D. Solecki, 2001b: Global environmental change and a
global city: Lessons for New York, Environment. 43(3): 8-18
31
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
Rosenzweig, C., S. Gaffin, and I. Parshall, eds., 2006: Green Roofs In The New
York Metropolitan Region. Research Report. Columbia University Center for
Climate Systems Research and NASA Goddard Institute for Space Studies.
New York.
Rosenzweig, C., W. Solecki, and R. Slosberg, 2006: Mitigating New York City’s
Heat Island with Urban Forestry, Living Roofs, and Light Surfaces,. Final
Report, New York City Regional Heat Island Initiative. Prepared for the New
York State Energy Research and Development Authority, NYSERDA
Contract #6681. New York.
Ruth, M. (ed.) 2006: Smart Growth and Climate Change, Edward Elgar
Publishers, Cheltenham, England, 403 pp.
Ruth, M., K. Donaghy and P.H. Kirshen (eds.). 2006: Regional Climate Change
and Variability: Impacts and Responses, Edward Elgar Publishers,
Cheltenham, England, 260 pp.
Ruth, M., C. Bernier, N. Jollands., In press: Adaptation to urban water supply
infrastructure to impacts from climate and socioeconomic changes: The
case of Hamilton, New Zealand, Water Resources Management.
Ruth, M., A. Amato, and P. Kirshen. 2006” Impacts of Changing Temperatures
on Heat-related Mortality in Urban Areas: The Issues and a Case Study
from Metropolitan Boston, [In Ruth, M. (ed.) 2006]. Smart Growth and
Climate Change, Edward Elgar Publishers, Cheltenham, England, pp. 364 –
392.
Ruth, M. and D. Coelho. forthcoming: Managing the interrelations among urban
infrastructure, population, and institutions, Global Environmental Change
Sherbinin, A., A. Schiller, and A. Pulsipher, 2006: The vulnerability of global
cities to climate hazards, Environment and Urbanization, 12(2). 93-102.
Solecki, W. D., and C. Rosenzweig: 2006: Climate change and the city:
Observations from metropolitan New York. In: Cities and Environmental
Change, [Bai, Xuemei (ed.)], Yale University Press, New York, (in press)
Solecki, W. and R. Leichenko, 2006: Urbanization and the metropolitan
environment, Environment, 48/4: 8-23.
Stone, B., 2006: Physical Planning and Urban Heat Island Formation, [In Ruth,
M. (ed.)] 2006. Smart Growth and Climate Change, Edward Elgar
Publishers, Cheltenham, England, pp. 318 – 341.
32
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
VanDeveer, S. and H. Selin, 2006: "Climate Leadership in Northeast North
America" paper presented at the Conference Climate Change Politics in
North America, Washington DC, May 18-19 2006,
http://www.wilsoncenter.org/ecsp.
Wilbanks, T. J. and others, 2003a: Possible responses to global climate change:
integrating mitigation and adaptation. Environment, 45/5, 28-38.
Wilbanks, T. J., 2003b: Geographic scaling issues in integrated assessments of
climate change. In: Scaling Issues in Integrated Assessment [Rotmans, J. and
D. Rothman (eds.)]. Swets and Zeitlinger, pp. 5-34
Wilbanks, T. J., 2003c: Integrating climate change and sustainable development in
a place-based context. In: Climate Policy. Supplement on Climate Change and
Sustainable Development, November 2003, pp. 147-154 \
Wilbanks et al., 2007: Toward An Integrated Analysis Of Mitigation And
Adaptation: Some Preliminary Findings, [In Wilbanks, Klein, and Sathaye,
(eds.)], Challenges in Integrating Mitigation and Adaptation as Responses to
Climate Change, special issue, Mitigation and Adaptation Strategies for
Global Change, forthcoming 2007.
Young, B., 2002: “Thinking Clean and Green”. In Georgia Trend, 18: 93-100.